An Unusual Etiology of Cauda Equina Syndrome in an AIDS Patient: A Case Report

Patients with advanced HIV/AIDS are at high risk for Primary central nervous system lymphoma (PCNSL) due to impaired immune surveillance and HIV-driven B-cell proliferation. While intracranial lesions are well recognized, spinal involvement remains underrecognized due to the scarcity of well-documented reported cases in the current literature. In this report, we describe the case of a 35-year-old male with a new HIV diagnosis who experienced acute bilateral lower extremity weakness and urinary retention during hospitalization for fever, perianal abscess, and urinary tract infection. Initial CD4 count revealed profound immunosuppression, with a CD4 count of less than 20 cells/μL and a viral load of 178,000 copies/mL. Spinal MRI demonstrated an enhancing mass at T2-T3, with surrounding edema extending to C5-C6 and multiple vertebral lesions, while brain MRI was unremarkable. Liver biopsy confirmed Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (DLBCL), establishing a diagnosis of AIDS-associated systemic lymphoma with secondary central nervous system (CNS) involvement presenting as cauda equina syndrome - a neurosurgical emergency with potential for irreversible paralysis. This case underscores the importance of early, comprehensive spinal imaging in HIV-positive patients with new-onset myelopathy or cauda equina symptoms.